import Foundation

public class ArrayStack {
    //储存的所有元素
    var items: [String]!
    //栈中元素的数量
    var count: Int!
    //栈的大小
    var n: Int!
    
    public init(n: Int) {
        self.items = [String]()
        self.count = 0
        self.n = n
    }
    
    public func push(_ str: String) {
        guard str.count > 0 else {
            return
        }
        self.items.append(str)
        self.count = self.items.count
        self.n += 1
    }
    
    public func pop() {
        guard count > 0 else {
            return
        }
    }
}
